OK - some more detail.

I can see 2 different Airline references one for each, and one ticket number!

The flight is:

Dublin to London HR (with Aer Lingus)
London HR to Newark (with Virgin Atlantic)

There is a 2 hour 25 minute window in HR on the way out & 7 hours 25 mins on the way back (shouldn't be a problem saying only check my bags to London on the way back as I want to sightsee??

Also, I there are two of us on the reservation, if you really don't recommend not getting on the 1st leg - could one of us go to Dublin & the other one join in London?

Thanks!